Effect of dietary fiber incorporation on the characteristics of pregnant sows slurry

Massé, D.I., Croteau, F., Masse, L., Bergeron, R., Bolduc, J., Ramonet, Y., Meunier-Salaün, M.C. and Robert, S. 2003. Effect of dietary fiber incorporation on the characteristics of pregnant sows slurry. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada 45: 6.7-6.12. Feeding pregnant sows with a bulky diet rich in dietary fibers could improve animal welfare without providing excessive feed energy. However, this type of diet would have an impact on manure volume and composition, and a diet treatment to improve sow welfare by reducing their persistent hunger cannot be recommended without examining its impact on manure composition and handling. This study investigated the effects of high-fiber diets on the daily production and physico-chemical characteristics of manure slurry from pregnant sows. Three isoenergetic diets, very high-fiber (VHF), high fiber (HF), and concentrated (C), were fed twice daily to two groups of four fourth parity pregnant sows. Fecal and urine production was measured separately on days 17 and 18 of the 21-day treatment period. Physico-chemical analyses were performed on a slurry sample (mixture of feces and urine). Dietary fiber addition significantly (P < 0.05) increased fecal mass but tended to decrease urine production. Consequently, manure slurry (feces plus urine) production was similar with all diets, but total solids (TS) content was significantly increased (P < 0.05) as fiber addition increased. Mean TS concentration was 3.8, 11.1, and 18.3% in the manure from sows fed the C, HF, and VHF diets, respectively. As a result, manure slurry consistency was changed from a liquid state (less than 10% TS) when the C diet was fed to a semi-solid state (TS content between 10 and 20%) with the two high fiber diets. The use of high fiber diets may thus cause a challenge with the liquid manure handling, storage, and land application systems currently used on many commercial farms. Other major changes in manure slurry characteristics due to dietary fiber incorporation included significant (P < 0.05) increases in apparent viscosity, total and soluble chemical oxygen demand, and volatile fatty acid concentrations. Total amount of mineral elements excreted in the manure slurry was not affected by dietary fiber addition.